.celda_principal {
		
		 background-image:url('images/encabezado.jpg'); 
		 background-repeat: no-repeat; 
		 background-position: left top;
		 border-left-style: solid; 
		 border-left-width: 1px; 
		 border-right-style: solid; 
		 border-right-width: 1px; 
		 border-top-width: 1px; 
		 border-bottom-width: 1px;
		 vertical-align: top
		
	}
	
	.celda_izquierda {
	
		background-image:url('images/background_left.jpg'); 
		background-repeat: no-repeat; 
		background-position: right top	
	
	}
	
	.celda_derecha {
	
		background-image:url('images/background_right.jpg'); 
		background-repeat: no-repeat; 
		background-position: left top	
	
	}